1. The Field of the Invention
The present invention relates to wireless networks, and more specifically, to using directional antennas to enhance wireless mesh networks.
2. Background and Relevant Art
Computer systems and related technology affect many aspects of society. Indeed, the computer system's ability to process information has transformed the way we live and work. Computer systems now commonly perform a host of tasks (e.g., word processing, scheduling, and database management) that prior to the advent of the computer system were performed manually. More recently, computer systems have been coupled to one another to form both wired and wireless computer networks over which the computer systems can communicate electronically to share data. As a result, many tasks performed at a computer system (e.g., voice communication, accessing electronic mail, electronic conferencing, web browsing) include electronic communication with one or more other computer systems via wired and/or wireless computer networks.
For example, a number of computer systems can be coupled to a data hub through corresponding wired connections (e.g., category 5 cable) to form a wired network (e.g., an Ethernet segment). Similarly, a number of wireless computer systems (commonly referred to as “stations”) can be coupled to a wireless access point (“AP”) through corresponding wireless connections (e.g., resulting from appropriate communication between radios) to form a wireless network (e.g., an IEEE 802.11 network). Further, a data hub and/or an AP can be connected to other data hubs, APs, or other network components, such as routers, gateways, and switches to form more complex networks (including both wired and wireless connections).
In some networks, interconnections between computer systems result in a mesh topology, where each computer system is redundantly connected to a number of other computer systems. Mesh networks provide increased connectivity and throughput since network traffic can be routed around congestion or failed computer systems (or other nodes). Full mesh networks (i.e., networks where each computer system is directly connected to every other computer system) provide the greatest level of redundancy. However in a wired network environment, full mesh networks are very expensive to implement at least in part due to cabling costs.
More recently, wireless devices have been connected to form wireless mesh networks. Wireless devices are particularly well suited for mesh network implementations since wireless devices are not constrained by cables. Thus, a joining wireless device within communication range of other wireless devices can join an existing mesh network without having to add any physical components (e.g., additional cables) at the other wireless devices. Accordingly, a wireless mesh network can be established in an ad hoc manner between a number of wireless devices that are within communication range of one another.
Wireless devices typically include an omni-directional antenna that facilitates communication with other wireless devices. The omni-directional antenna is used to both transmit data to other wireless devices and receive data from other wireless devices. When no physical barriers exist (e.g., walls, floors, buildings, etc.), the range of the omni-directional antenna essentially results in a spherical region around a corresponding wireless device. Thus, for two wireless devices to meaningfully communicate, the spheres resulting from each wireless device's omni-directional antenna must at least partially overlap. That is, within the particular range, radio signals transmitted from one of the wireless devices will have sufficient signal strength such that, when received, the radio signals are meaningful to the other wireless device.
However, due to the distance and physical barriers separating wireless devices as well as channel interference, wireless communication is often difficult, and at times impossible. For example, when one wireless device is at or near the range of an omni-directional antenna at another wireless device and/or is separated from the omni-directional antenna by physical barriers, radio signal propagation loss (e.g., in the 2.4 GHz band or 5 GHz band) can potentially reduce the speed and reliability of data transferred between the two wireless devices. It may also be that other interfering devices, such as, for example, cordless telephones and microwave ovens, emit signals into a frequency band used for wireless communication. Signals emitted from interfering devices can degrade communication between wireless devices.
When wireless devices are outside the range of one another's omni-directional antennas, when substantial physical barriers separate the wireless devices, and/or when a channel is significantly degraded due to interference, meaningful communication between the wireless devices may not be possible. For example, due to a combination of wall absorption and channel interference, a data rate can be significantly reduced essentially making communication through an omni-directional antenna impossible. Further, while an omni-directional antenna may have sufficient signal strength to detect that radio waves are being received, the signal strength of the received waves may be degraded such that it is difficult, or even impossible, to determine what data is being represented by the radio waves.
As a result of difficulties typical in wireless communication, routing protocols have been developed that allow intermediary wireless devices to route or repeat data such that the data can be transferred from a sending wireless device to a receiving wireless device. For example, a sending wireless device can send data to an intermediary wireless device that in turn forwards the data to a receiving wireless device. Thus, wireless devices that are out of range of corresponding omni-directional antennas or that are separated by physical barriers have an increased chance of being able to exchange data. However, the use of these routing protocols still requires a chain of connectively between wireless devices. If a sending or intermediate wireless device cannot communicate with any other wireless devices that are closer to a receiving wireless device, data may not get forwarded to the receiving wireless device. Therefore systems, methods, and computer program products for using directional antenna to enhance wireless mesh networks would be advantageous.